RepRap Lewis was a design study for 3 axis motion with limited non-3D printable components. The design combined a SCARA arm for XY motion with a Sarrus linkage for Z, allowing for a cylindrical build area. While not mechanically ideal, this allows for minimal structural elements and a high ratio of printable area to machine volume. The design was built using parametric deign in OpenSCAD and made use of the Magpie hardware library I developed. As parameters were changed, a complete Bill of Materials would be output.
https://github.com/sjkelly/RepRap-Lewis
S. J. Kelly 